According to this, I burn about 720 calories per hour running (7 miles or so), around 720 calories per hour biking (assuming 13 mph, the max on the list; my long rides are usually 16 to 18 mph so maybe I should calculate more?), and over 900 calories per hour of continuous swimming.

Do these estimates seem about right (male, 160 lbs)? How do you estimate your own calories burned?

For what its worth, I was just on a compu trainer for a hard 80 min workout in a FTP class. At the end of 80 mins, I had burned 750 calories. So your cycling numbers seems a bit high. The calorie number is based on watts and my weight (155lb).

I've always heard, you burn about 100 calories a mile running. So that number seems in line with your thinking...

I have a heart rate monitor that outputs calories burned based on my HR and my weight (which I input and update at 10 lb intervals) and that's how I get my calories burned. You can get one for fairly inexpensive now...I saw one at dicks for $60. Mine was around $100.

For running is very easy:
km x your weight = calories bruned (and this will be indipendent from anything like speed, time, etc.)

For Swimming, there are studies on this but you can consider 10.5cal per minute at 3000yds/hour speed.
For easy to use, you can apply on Excel a formula where your calories are
10.5/3000*speed*time
where speed is your average speed you kept during training and time is the length f your training

For cycling it is a bit more difficult but, going around web or using any Polar HRM you will see that for a long ride outside you will be at around 12cals/min
On the trainer things can be different since intensities are high but if you consider warmup and cooldown times, you will be at around 11cals/min

Anyway, the best is to use an HRM and check: you will see my running formula very well applied.
Cycling will be more personal.

I do not think they are right. Swimming burns thew least amount of calories (behind running and then cycling) but your figures have them in opposite order. If I run 1 mile at 7mph I will burn around 1,100 caloris (6' tall and 196 lbs). However if I swim for 1 hour I'm lucky to burn 600.

I do not think they are right. Swimming burns thew least amount of calories (behind running and then cycling) but your figures have them in opposite order. If I run 1 mile at 7mph I will burn around 1,100 caloris (6' tall and 196 lbs). However if I swim for 1 hour I'm lucky to burn 600.

That's correct. Running is the most expensive sport.
Assuming of course that your are not too bad in swimming and that you do not swimm too fast (like 4000 yds/hr).
Look at this link http://www.indiana.edu/~hplab/research/estimates_of_swimming_energy...
Again for running, DON'T look at the speed, just distance! it is much easier.
You said 1 mile: 1.6km x your weight (in kg) = 1,6x88,9 = 142,4. That's it. Indipendently of your speed.
If you take 20 seconds for that mile or 20 minutes, it doesn't matter. Same energy spent.

I created a small program that calculates your calories burned based on your weight, duration and activity. The calculations are based on MET (metabolic equivalent level). I think all calculators are just an estimate and most seem to come fairly close to one another. I will try to attach a zip with the program but if the forum will not allow me to upload it and anyone wants it then just PM me and I will send it to you.